With the continuous improvement of people's quality of life, solid wood floorings become more and more popular. Existing solid wood floorings can generally be classified into pure solid wood floorings made by log processing and engineered wood flooring. Pure solid wood floorings completely retain the original state of natural lumber and have a true and beautiful texture, and high degree of environmental protection. They also have many advantages, such as fine appearance, high grade, natural and environmental friendly, etc. However, pure solid wood floorings have a large deformation rate and they will swell or shrink and easily warp under changes in air temperature or humidity, leading to bad use effect.
Engineered wood floorings are made by layered process so that each timber mutually restrains each other and a certain degree of internal stress can be offset. The deformation rate of engineered wood floorings is lower than that of pure solid wood floorings, such as the laminate floorings with two layers staggering disclosed in patent CN2438558Y. However, due to the difference in materials' density and moisture content of surface layer and substrate, layered deformation and warp occur easily for engineered wood floorings under the effect of environmental temperature or humidity, etc. Patent CN202062479U discloses a doorframe-type solid wood plank. It has the doorframe-type bounded structure formed by setting a liner in the frame, improving the anti-bending deformation performance of the solid wood plank to prevent the bump and contracting inward.